[N&W] Re: Baker valve gear

nw-mailing-list at nwhs.org nw-mailing-list at nwhs.org
Tue May 4 23:16:58 EDT 2004

[Ed King writes:]

N&W first used Walschaerts on E-1 Pacifics and M-1 4-8-0s in 1907.

First Baker application was to the E-2 Pacifics in 1910 as the original
Baker-Pilliod gear (Baker was designed by Abner D. Baker and manufactured by
the Pilliod Co.)   It was modified for greater simplicity and sold as Baker
gear, N&W's first use of the modified product being on the M-2a, M-2b and
M-2c 4-8-0s of 1911.  The E-2s were converted to Baker, date unknown.  The
Walschaerts on the E-1s and M-1s was of an unfortunate design that promoted
rapid wear of the link blocks.  This drove the N&W into the arms of Baker
even though later Walschaerts engines were more satisfactory.

Baker has the advantages in that all its connections are radial - pins and
bushings which are easy to maintain on a lathe - and lend themselves to
roller bearing applications as was done on all new N&W power after A 1205 in
1937.  There is no link nor sliding link block to maintain.  It will stay
true longer than gears using the sliding link block - Stephenson,
Walschaerts, Southern and Young.  Walschaerts had the advantage that its
patents had run out long, long ago and no one had to seek licensing to
manufacture it.  There were railroads which did not use Baker because it had
to be bought from an outside manufacturer.

How it works was described so that anyone can understand it in TRAINS
Magazine back in ought-'84. Diagrams were included.  If you can't find the
article (entitled Decoding Stephenson, Walschaerts, Baker, Southern and
Young), send me a SASE and I'll send you a Xerox copy of mine.  The address
is 10265 Ulmerton Rd., #197, Largo, Fl. 33771.

Ed King

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